I don't love your title. In fact, it turns me off a bit, so whatever that's worth. After reading the synopsis, I don't think the title does the story justice.
I really liked the first lines of your synopsis. I'd just be careful using the word "here".
If the angels sense (or maybe a more sucinct word is "find) she is
here, (on earth, in the human world- be more specific) they’ll kill her After using Forced to use her energy to take down a violent tenant, Sam's worries her presence may be revealed. Her worst fears are realized when an angel walks into a bar during a Friday business happy hour, clearly looking for someone comes looking for her. Sam manages to crawl out the back while the humans are busy adoring the angel evade him, and races for the gate to take her safely back to her homeland, but changes her mind at the last minute. Halfway there, Sam changes her mind. Although she sometimes longs for home, How can she leave the life she's so carefully built? How can she abandon and deny what she feels for Wyatt? The truth is she can't, so she determines to live more stealthily than ever, but staying under the radar isn't as easy as it sounds. she’s built a life here amidst the humans, with things she enjoys and of course, Wyatt, who she feels strangely human emotions for. Unable to leave it all behind, she decides to stay and keep on with her life as stealthy as she can in the hope that she can hide out from the angel.
First, she reveals her true self to Wyatt in a moment of passion, jeopardizing not only their new relationship, but also their friendship. Then while investigating an attack on her dog, Sam kills
what appears to be a crazy, mutated human. Fearing her bold action will call down the angels, Sam is surprised to discover she's attracted the attention of an entirely different group of supernatural beings- the werewolves. Apparantly, the man she killed was one of them and She waits nervously to see if her actions have been noticed, but instead of an angel at her door she finds a woman claiming that the man she killed was a werewolf and that she now owes them a service as payment for the his death. The service payment they demand is outrageous – killing a rogue angel named ALTHEAN who is trying to exterminate their species. The werewolves blackmailed her with threats of banishment, and she fears not only for herself, but for Wyatt who the angels will find guilty by association. Sam Reluctantly , she agrees to help the werewolves take down their nemesis.
Sam, Wyatt, and the meticulously groomed werewolf, CANDY (Love, love love a werewolf named Candy) track down the killer using a mix of old fashioned detective work, computer predictive modeling and CSI,
all flavored with their own special skills. Through the search, Wyatt begins to accept Sam as a demon and they tentatively move their relationship forward (Maybe express this less formally- it feels stiff- maybe say "Wyatt warms to her- something with more feeling and romance since that's what you are talking about). When the three nearly take down Althean at his next kill they unfortunately tip off the Avenging Angel Gregory whose specialty is exterminating demons like Sam. (hate this as an Angel name by the way- it needs to be something way more kick-ass than Gregory) another angel to Sam’s presence. This angel is far more powerful than the one they are tracking, and his goal is to kill every demon he finds without hesitation. When Gregory descends, intent on Before he can decapitating Sam, Wyatt shoots the angel in him in the head, distracting him enough for Sam to blast him with all she’s got and escape. Instead of acting in self preservation (This confuses me because you just said she blasted Gregory and escaped -then suddenly she's captured? May need a more detailed explanation here. Does she come back to save Wyatt? How does that go down?), Sam endangers herself to save Wyatt from the angel’s wrath. Intrigued, the angel Gregory decides to keep her alive long enough to help him catch the rogue Althean. Now Sam is really in trouble. This new angel, called GREGORY, Gregory won’t let her out of his sight, and he’s made it clear her days are numbered. She tries to escape, but only infuriates him to the point that he magically binds her. Now that Sam is bound her chances of escape are miniscule, and Wyatt is in danger too as her “toy” (makes it sound like she sees him as a toy. I know this is Gregory's take on it, but I say stick with Sam's POV. Maybe use the word accomplice- human familiar?).
The longer Gregory spends with Sam though, the more
he begins to see her as more than a lowly cockroach of an imp. He sees that she still holds qualities of the angels that the demons once were.
As he watches her play with lightening in a thunderstorm, Growing nostalgic, Gregory grows nostalgic, and tells Sam he will allow her to decides to let Sam go home. Immediately. Afraid he will change his mind, Sam she flees for the nearest gate to take her back to her homeland, only to again change her mind. but she just can't bring herself to pass through it. She hates the thought of life doesn't want to live without Wyatt. The angels are hypocrites, especially Gregory, who isn't going to punish Althean for all the murders he's don't and she just can't leave the service she owes the werewolves undone.(Make this change of mind compelling and stronger- like the first time is was just a silly whim but this time she's pissed and gotten some balls- otherwise I feel like she's just a ditz who can't make up her mind) She also finds herself bothered by the seeming hypocrisy of the angels, and Gregory in particular. She’s not sure Gregory will kill or even punish Althean for the murders he has done, and she just can’t leave that question about him unsettled.
Gregory is shocked to see her again, but knows her skills will be useful in helping him finally catch Althean (Wait, she goes back to Gregory? WHY? I'd much rather see her do this on her own and totally thwart all the angels). Together they manage to confront him, and kill him. In the battle, Sam finds herself mortally wounded and convinces Gregory to end her life himself, preventing the energy within her from exploding out and killing thousands of humans.
Worrying about collateral damage isn’t very demonic, but Sam has become more human over the years and at this moment she finds herself valuing their lives. Gregory has killed every demon he’s met since the Demon Wars, but Sam is different. Gregory cannot kill her. He heals Sam, although the energy she holds almost overwhelms him. At the end, he allows her to stay, with certain behavioral standards she must keep. She heads home with Wyatt. Sam now has permission to continue her human life without fear of being killed by the angels; she has a boyfriend she cares about who accepts her as a demon. And she’ll be home in time to make the Monday morning Zumba class.
(To me this ending seems to take the heroic action away from your protagonist, Sam, and put it in the hands of Gregory who saves her. I really liked the plot up to the point she returns to Gregory. After that, you lose me by making Gregory the hero of your story and even allowing him to put restrictions on Sam's which doesn't feel like a victorious, satisfying ending at all).
Those are just my thoughts. Hope something helps. I have a synopsis up to0 and would appreciate any reciprocation.